Developing the National
Geologic Map Database

David R. Soller and Thomas M. Berg

[Originally published in the June, 1995 issue of Geotimes (American Geological Institute, Alexandria, VA; ""; e-mail "". Reproduced by permission.]

With increasing frequency, people are using the Internet to explore and identify new sources of information offered by the government, corporations, and universities. This information is accessed by people with widely varying needs, including schoolchildren, public planners and decisionmakers, research scientists, corporate decisionmakers and researchers, and congressional staff members. Commercial and public-domain software (for example, the hypertext-based World-Wide Web supported by the Mosaic graphical user interface) allows even the Internet novice to search the data holdings of organizations worldwide, and to communicate directly with data producers and database administrators.

The software, when used to navigate the Internet, is a revolutionary tool for both data users and producers. It provides users with unprecedented access to information and, at the same time, allows data producers such as academic institutions, corporations, and government agencies to market and to share their information. Geoscientists have long maintained that their geologic maps, derivative maps, and related information serve a vital role in supporting public and private decision-making, general education, and advances in scientific research.

As useful as this information may be, it is located at many agencies and institutions, and is not easily accessible by most people. Through personal contact with individual companies, agencies, universities, or through extensive library searches-requiring persistence and patience-a person can locate pertinent earth-science information. To an Internet user, this cumbersome process is no longer acceptable. Furthermore, users are demanding information in digital format-note, for example, the rapid growth in the use of computer-based geographic information systems (GIS) by public agencies, private firms, and academia.

The geoscience community is painfully aware that state and federal legislatures are increasingly questioning the need for government geoscience agencies-most notably, this year's congressional debate about abolishment, privatization, or further downsizing of the U.S. Geological Survey (USGS). It is in our best interest to make the public more aware of the relevance and value of our information. To do this, we must develop on-line systems to search the various repositories of earth-science information in paper and digital format and provide access to it.


Two recent federal mandates support these objectives. First, the National Geologic Mapping Act of 1992 (PL 102-285) specified that the USGS develop a National Geologic Map Database as a national archive containing geologic maps and related databases. The act stated that the database was to be developed as soon as practicable, through "...cooperation with state geological surveys, other federal and state agencies, public and private sector organizations, and academia." The database must contain geologic, geophysical, geochemical, geochronologic, and paleontologic information.

Second, on April 11, 1994, President Clinton signed Executive Order 12906, establishing the National Spatial Data 'Infrastructure (NSDI), which will include a National Geospatial Data Clearinghouse. The Clearinghouse will help users find information by performing keyword or geographic searches of metadata (brief descriptions of individual data sets). In the past few months, prototype versions of the clearinghouse have been developed. To view the USGS prototype clearinghouse, access the USGS home page through the World-Wide Web by specifying URL "", and select the NSDI icon.

The president's executive order also specifies that standards will be developed by the Federal Geographic Data Committee (FGDC). Those standards will facilitate the efficient search, transfer, and use of both metadata and the actual data sets. Subcommittees (each focusing on a specific subject, such as cadastral records, soils, geology) will work to improve the sharing of information, in part by developing standards. The USGS chairs FGDC's Geologic Data Subcommittee.


The database has not been fully designed yet, but we believe it should be centrally coordinated and based on widely accepted standards for information content and format. Rather than operating as a monolithic entity, it should be a distributed system, composed of many computers where the data are stored (fileservers) but with a single national point of public access for browsing and query.

The database could be accessed as follows:

Selecting one of the options for further research would allow the user to connect to the particular fileserver where the selected data set resides. With this design, data holdings of each state geological survey could be linked with those of the USGS into what would appear to be, from the user's perspective, a single unified database. Whether a user would be allowed access to an actual data set would be decided by the organization holding that data. However, free access to the metadata would clearly benefit all data producers by publicizing the availability of information.

To develop a comprehensive, distributed National Geologic Map Database, we need the advice of the geoscience community on many issues: developing standards for information content and data format, and for metadata needed to support the database design; identifying organizations with similar databases; assisting in the development of a comprehensive index of map information; identifying pertinent data sets; and helping to develop a useful interface for public access to the database.

To accomplish these goals as quickly as possible, a spirit of cooperation, and an investment of resources are necessary. Cooperation will be especially important as we develop the standards necessary to permit information from varied sources to be accessed under a single search-and-retrieval system. The potential list of contributors to the database emphasizes the need for standards. Contributors may include the USGS, 50 state surveys, commercial firms, local and state governments, academic institutions, related federal agencies, and tribal governments.

Consider the most basic requirement of the database - a comprehensive listing of earth-science information, available either in paper or digital format. For years, the USGS maintained the Geologic Map Index, a national inventory of geologic mapping. The latest version was released in 1991 as a USGS Open File Report (91-575-A and B). It is imperative that the database contain a more up-to-date and comprehensive inventory of all geologic, geophysical, geochemical, paleontologic, and geochronologic spatial information. That inventory, composed of metadata, must be searchable by such efficient search techniques as the Wide Area Information Server (WAIS) which is based on standard protocols (that is, a standard named Z39.50) for searching file indexes. For the database search to work properly, all metadata accessible to the central search computer must conform to an agreed-upon standard. We must work together to develop such standards and to meet the urgent, day-to-day practical needs of taxpaying citizens.

How can the geoscience community help? Some issues - standards in particular - will be addressed through the FGDC Geologic Data Subcommittee and through formal channels established between the USGS and the Association of American State Geologists. But there is great value in informal and unsolicited advice from experts. To this end, we will establish a venue for comments (via e-mail) on specific issues through announcement of request in the USGS home page.

David R. Soller

USGS, 908 National Center, Reston, Va. 22092
A research geologist, Soller serves as acting deputy chief for Digital Mapping in the Office of Regional Geology, Geologic Division. His responsibilities include coordinating the design of the National Geologic Map Database and serving as executive secretary of the FGDC Geologic Data Subcommittee.

Thomas M. Berg

Ohio Department of Natural Resources, Division of Geological Survey, 4383 Fountain Square Drive, Columbus, Ohio 43224-1362
Berg is state geologist of Ohio, and chair of the Digital Data and Standards Committee of the Association of American State Geologists.>

Additional Reading

For information about the FGDC and NSDI, contact FGDC Secretariat, c/o U.S. Geological Survey, 590 National Center, Reston, Va. 22092. World-Wide Web address: "". E-mail address: ""

Promoting the National Spatial Data Infrastructure Through Partnerships. Mapping Science Committee of the National Research Council (National Academy Press, Washington, D.C.) 1994

The Whole Internet-User's Guide and Catalog by Ed Krol. Second edition. 0'Reilly and Associates Inc. (Sebastopol, Calif.), 543 p., 1994

National Geologic Mapping Act of 1992, PL 102-285.102nd Congress

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